JP2011171713A - Pattern definition device with multiple multi-beam array - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-beam pattern defining (PD) system, capable of correcting a distortion error in an image forming system and a charged particle processing or inspecting apparatus. <P>SOLUTION: An aperture array means (202) includes at least two sets of apertures (221, 222) to determine respective beamlets (b1-b5). Here, the sets of apertures include a plurality of apertures arranged in an intermingled arrangement and different sets of apertures are offset from one another by a common displacement vector (dl2). An opening array means (201) has a plurality of openings (210), although configured, to allow a subset of beamlets corresponding to one of the sets of apertures to pass through, but it does not have an opening (to allow the beam to pass through), at a position corresponding to the other sets of apertures. A positioning means moves the aperture array means in cooperation with the opening array means, in order to selectively align one of the sets of apertures with an opening of the opening array means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multi-beam pattern definition device used in a particle beam processing or inspection device. The device is adapted to be irradiated with a beam of charged particles, in particular ions, allowing the beam to pass through a plurality of apertures, thus forming a corresponding number of beamlets. The apparatus includes aperture array means in which the aperture is realized and hole array means having a plurality of holes configured for passage of at least a subset of the beamlets formed by the aperture.

The invention also relates to a method of using such a multi-beam pattern definition device, in particular a method of using a multi-pass method for multi-beam writing to a particle beam processing or inspection device.

Particle lithography and processing are used in semiconductor production and microstructure applications. Direct patterning, particularly by ion beam irradiation, is a promising concept for future industrial manufacturing in high-resolution nanoscale devices, especially nodes of 32 nm and 22 nm and below. An apparatus for patterning a charged particle beam (especially an ion beam) to include a desired design pattern—referred to as a pattern definition apparatus (PD apparatus) —is preferably a plurality of programmable aperture devices, the aperture of which Designed to form beamlets that illuminate the device from the beam, selectively keeping some beamlets on their paths and redirecting other beamlets, the latter on the target surface It can be programmed not to reach the board according to the desired design pattern to be created. Implementation of multi-beam projection optics based on programmable multi-aperture plates has enabled significant improvements in achievable productivity compared to a converged single beam system. The reasons for improved productivity are firstly the parallel structure of the process using multiple beams and secondly the increase in current that can be imaged on the substrate with the same resolution. Both are made possible by significantly reduced Coulomb interactions in the beam. Furthermore, the moderate current density associated with the projection optics increases processing speed when the precursor gas is used for a beam induced chemical process. Compared to a focused beam system, it can also prevent a reduction in heating effect due to extreme beam intensity.

US Pat. No. 6,768,125 US Application No. 2009/0200495 A1

Particle beam devices and associated aperture array means are disclosed in Assignee / Applicant US Pat. No. 6,768,125 and US Application No. 2009/0200495 A1. These documents implement the multi-beam direct writing concept and an aperture plate system (APS) programmable as a pattern definition (PD) device for assembling a particle beam extracted from a single source of charged particles. A processing method and apparatus called charged particle lithography and PML2 (abbreviation of “projection maskless lithography”) are described.

  APSs are generally configured as a continuous stack of plates, i.e. aperture array means (aperture plates), deflection array means (mekura plates) and possibly additional plates such as cover plates or interspersed correction plates And many devices realized as hole array means. The aperture plate includes an array of apertures that define a beam pattern of beamlets projected onto the target surface. A corresponding blanking opening on the mekra plate is associated with the opening. The blanking aperture is positioned such that each beamlet traverses a blanking aperture corresponding to the aperture that defines the beamlet. Each blanking aperture is in a first state ("switch-on") in which the beamlet deflection means exhibits two deflection states, i.e., the particles passing through the aperture can move along the desired path. )) And a second state (“switched off”) in which the beamlet deflecting means deflects particles transmitted through the aperture away from the passage and can be controlled by a blanking signal Is provided. Additional cover plates are placed in front of other plates to protect other plates from the impact of incoming beams, except in the area where the beamlets are made. In addition, correction plates exist to introduce specific corrections in the direction of the beamlets to achieve special imaging characteristics, such as correction of imaging defects or adjustment of cross aberrations.

As disclosed in US Pat. No. 6,768,125 and related prior art, in the PML2 layout, the position of the patterned beam on the target moves one pixel of the target under the optics. It is held fixed at the corresponding pixel location only for the duration. The patterned beam then jumps to the next pixel location that is adjacent to the previous one. Thus, each beamlet is applied to an adjacent pixel on the target. A variation of this method that significantly reduces data transfer at / to the APS is discussed in assignee / applicant's US Patent Application No. 2008/0237460 A1, where each beamlet contains multiple pixels. It is fixed at the (moving) position of each pixel on the target, even for a longer duration, corresponding to the pixel exposure cycle of the target movement by the distance covered. As a result, the beamlet is therefore deflected by the deflection system of the imaging optics (deflector 16 in FIG. 1).

  Modern PD devices have a fixed arrangement of openings. Accordingly, the PD device should change if the target is processed with a pattern portion having a different critical dimension (ie, the length dimension of the smallest feature created). It is an object of the present invention to find a way to make a PD device more flexible and to realize multiple shapes of aperture arrangement.

  According to a first aspect of the present invention, a multi-beam pattern definition device of the kind first mentioned and having an aperture array means and a hole array means is provided with the following configuration: “Multiple beam arrays” The aperture array means comprises at least two sets of apertures, each comprising a plurality of apertures arranged in an (essentially) regular arrangement on the aperture array, the arrangement of the set, at least partially woven Interlaces, where the different sets of apertures are at least in the region where the arrangements are interlaced and offset by movements corresponding to a common movement vector. Correspondingly, a plurality of apertures of an aperture array configured for passage of at least a subset of beamlets formed by the apertures, at least in a region corresponding to the interlaced region of the aperture array means Includes a plurality of apertures arranged in an essentially regular arrangement, and lacks apertures in the area corresponding to the set apertures of the region and other apertures (the hole array means is impervious there. The arrangement corresponds to an arrangement of one of the openings of the set.

More conveniently, positioning means for arranging the aperture array means and / or the hole array means are provided for adjusting the positions of the aperture array means and the hole array means relative to each other. These positioning means selectively select one of the sets of openings of the aperture array means, i.e. the selected set of the plurality of hole array means, so that the openings and holes align at least in the interlaced region of the arrangement. Configured to align with the opening.

In a typical implementation of the invention, the openings in each set have an equivalent shape and size, while the different sets of openings differ in their size and / or shape. Furthermore, in a suitable embodiment of the invention, the aperture array means and the at least one hole array means are designed to be oriented essentially perpendicular to the beam and arranged in the path of the beam. It is realized as a plate-like device having a film part.

The present invention allows the realization of different critical dimension values within a PD system by simply switching the geometric spot size. The spot size is determined by the size of the aperture and can therefore be selected by activation of a suitable aperture set. In particular, a larger spot size can be chosen for less important areas or patterning elements on the target, while a smaller spot size is used only for the most important pattern element applications. This increases the production efficiency.

  Another advantage of the present invention is that it allows adjustment of the current through the projection system in view of the blur associated with Coulomb interactions, especially when different ion types are used. In this context, it is noted that higher particle amounts result in greater blurring; this can be corrected using different beamlet widths, which instead cause a different overall current beam ( Suppose the number of beamlets is kept constant).

Furthermore, different aperture sets can be used for different tasks of particle beam devices such as motion and pattern lock testing, beam calibration, and accurate target writing.

In a further development of the invention, in particular in line with the PML2 concept, the deflection array means, for example in the form of a so-called mekra plate, are positioned so that each beamlet traverses one of the blanking openings along the nominal path. A plurality of blanking apertures, wherein the deflection array means is associated with each of the ranking apertures, and when an operating electrical voltage is applied to each electrode, its nominal A plurality of electrostatic deflection electrodes configured to deflect the beamlets traversing each blanking aperture by an amount sufficient to deflect the beamlets away from the passageway. In addition, the electrodes are individually provided with connecting lines for applying electrostatic potentials, with associated counter electrodes and actuated for each counter electrode by an amount sufficient to deflect the beamlet away from its nominal path. When a voltage is applied, the beamlet traversing each blanking aperture is configured to be deflected.

  The apparatus of the present invention includes hole array means separate from the deflection array means. This hole array means implements a cover plate or beam selection plate located between the other plate components of the apparatus.

In a simple realization of the invention, the deflection array means (mekra plate) is configured as a hole array means. In this case, it is advantageous to determine the orientation of this component so that it is located on the side of the deflection array means that is oriented away from the incoming beam.

  The set of apertures covers different areas on the area of the aperture array means that can be used to expose areas on the target with different die sizes. Spatially large or small beam arrays allow implementation of various requirements for optical blurring and writing strategies. For this purpose, the aperture set preferably extends over different but overlapping areas on the aperture array means, preferably realizing a continuously increasing area where one area is included in the next area.

  In another development of the invention, the positioning means are arranged to adjust the position of the aperture array means only, while the hole array means and possibly the deflection array means (mecla plate) are also the device. Fixed within.

The placement of the apertures in the set of apertures is introduced by, for example, an imaging error of the projection system used to project the pattern created in the PD device onto the target to introduce a certain predistortion of the patterned beam Slightly changes to compensate for distortion. In this case, the position of at least one of the apertures in the set of apertures is displaced from the exact position of the rectangular or diagonal grid by fine positioning movements, and these fine positioning movements of the projection system operated in conjunction with the apparatus. Correcting the imaging error, where the position of each aperture, including its fine placement movement, enters the area defined by the projection of the corresponding hole of the hole array means onto the aperture array means, and the aperture array means If each set of apertures is aligned with a plurality of holes in the hole array means, the projection is along the direction of the beam.

  Of course, various sets of apertures exist with different fine distributions and provide different predistortions to the patterned beam. Thus, beam predistortion is used to resolve a single beam position vector or group of beam position vectors relative to other beams (eg, by a simple knife edge in a Faraday cup) and to calculate the strain state. After calibration of the original position performed by scanning the beam array with a beam position detector that uses position information, it can be changed by choosing the most appropriate aperture set.

  In addition, the aperture array means includes several sub-areas with openings that do not even overlap (or overlap only slightly); in this aspect of the invention, the positioning means moves the aperture array means towards the different sub-areas. Must provide enough offset range to move.

  In the apparatus of the present invention, a method comprising the following steps can be used to achieve alignment between one of the set of apertures and the holes of the hole array means: (i) of the apparatus with a beam of charged particles Irradiation, (ii) measurement of the current delivered by the device as a function of changing the relative position indication of the aperture array means and the hole array means with respect to the positioning parameters, (iii) positioning parameters for the maximum value of the transmitted current And (iv) adjusting the positioning of the aperture array means associated with the hole array means according to the value of the positioning parameter.

  The present invention is useful for multi-pass writing methods where each pass has a different characteristic of exposure, eg, different critical dimensions. Such a method for multi-beam writing in a particle beam processing or inspection device using a multi-beam pattern definition device according to the invention comprises the following steps: (i) a target using a multi-beam pattern definition device Writing a first pattern to the upper surface area, wherein the first set of openings of the aperture array means is aligned with the holes of the hole array means; (ii) the second of the openings of the aperture array means Adjusting the positioning of the aperture array means such that the set of holes is aligned with the holes of the hole array means, and (iii) writing a second pattern on the surface area on the target. Steps (ii) and (iii) are repeated as required for different sets of apertures.

In the following, the invention will be described in more detail with reference to the drawings, each shown in schematic form:
FIG. 1 shows an overview of a particle beam exposure apparatus suitable for the present invention in the vertical section; FIG. 2 shows a top view of the PD system; FIG. 3 shows a side view and a partial view of the PD system of FIG. 2 (one on each side, left and right); FIG. 4 shows partial details of a PD configuration of the present invention having a three-plate configuration in which the aperture plate includes two sets of apertures, with the first set of apertures operating; FIG. 4a is a variation of FIG. 4 of the aperture plate moved to actuate the second set of apertures; FIG. 5 shows a top view of a portion of the PD configuration corresponding to FIG. 4; 6 shows a top view of a portion of the aperture plate of the PD configuration of FIG. 4; FIG. 7 shows the positioning control of the aperture plate in the PD configuration; FIG. 8 shows a variation of a PD configuration having a two-plate configuration; FIG. 9 shows another variation of a PD configuration having a three plate configuration; FIG. 10 shows a variation of the aperture plate with three sets of apertures; FIG. 11 shows another variation of the aperture plate in which the aperture set is a different size; FIG. 12 shows yet another variation of the aperture plate in which one of the aperture sets includes fine placement deflection to correct imaging defects.

The preferred embodiments of the present invention discussed below are of the PML2 type as disclosed in the above-mentioned US Pat. No. 6,768,125 and US Patent Application No. 2009/0200495 A1 with greatly reduced projection systems. Development of a particle beam exposure apparatus and its pattern definition (PD) system. In the following, first the technical background of the apparatus will be discussed as far as it relates to the present invention, then embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments or a specific layout of a PD system that merely represents examples of possible embodiments of the invention, but rather the invention uses particle beam and multi-beam patterning as well. It should be appreciated that it is suitable for other types of processing systems.

PML2 System A schematic overview of a maskless particle beam processing apparatus PML2 used in the present invention is shown in FIG. In the following, only those details will be given as it is necessary to disclose the invention; for clarity, the components are not shown in the size of FIG. 1, and in particular the lateral width of the particle beam is exaggerated. For details, reference is made to US Pat. No. 6,768,125 and US Patent Application No. 2009/0200495 A1, whose teachings regarding the overall layout of the particle beam device and PD means are included herein by reference.

  As already mentioned, the particle beam generated by the particle source is used in the PML2 system. The illumination optics creates a wide beam that illuminates the PD means with a regular array of apertures with the beam to define a beam pattern projected onto the target surface. At each aperture, a small beam (also called a “beamlet”) is defined, allowing the passage of the beam's particles through each aperture towards the target (“switched on”) or effectively stopped. It is possible to control the passage of each beam through the aperture in such a way (“switched off”). The beam that travels through the aperture array forms a patterned particle beam with pattern information represented by the spatial arrangement of the apertures. The patterned beam is then projected onto a target (eg, a semiconductor substrate) by a particle optical projection system, where an image of the aperture is thus formed to modify the target at the illuminated part. The image formed by the beam is moved along a linear path over the area of each die; an additional scan of the beam perpendicular to the scan direction (corrects the run error next to the scan stage) Not needed) unless needed.

In this example, the main components of the apparatus 100 in the direction of the lithography beam lb, pb that moves vertically downward in FIG. 1 are: an illumination system 101, a PD system 102, a projection system 103, and a target or substrate 14 And a target station 104 having The particle optical systems 101 and 103 are realized using electrostatic or electromagnetic lenses. The electro-optical components 101, 102, 103 of the device 100 are contained in a vacuum housing (not shown) held in a high vacuum to ensure unimpeded propagation of the beams lb, pb along the optical axis of the device. It is.

  The illumination system 101 includes, for example, an ion source 11, an extractor arrangement that determines the location of the virtual source, a particle filter / general blanker 12, and an illumination optical system realized by a condenser lens system 13. The ions used can be, for example, hydrogen ions or heavy ions; in the context of this disclosure, heavy ions are heavier than C, for example O, N, or noble gases Ne, Ar, Kr, Xe Refers to the ion of an element. Apart from ions, the particles can be electrons (emitted from an electron gun) or, in general, other charged particles can be used as well.

The ion source 11 has a defined (kinetic) energy of a few keV, for example with a relatively small energy spread of ΔE = 1 eV (eg 5 keV in the PD system 102), and is mainly of particular type such as hydrogen or Ar + ions. Emits various types of energy ions. The velocity / energy dependent filter 12 serves to filter other unwanted particle types that are also created at the source 11; the filter 12 also generally moves the beamlet to another location. Used to turn off the beam. By means of the electro-optic condensing lens system 13, the ions emitted from the source 11 are created into an essentially telecentric ion beam which serves as the lithographic beam lb in a wide range. The telecentricity of the beam is in the range of ± 25 μrad deviation from the optical axis at the position of the PD device, where 200 times the volume reduction system and the PD device and the substrate have the same particle energy, assuming the substrate position to be from the optical axis. This leads to a range of telecentricity of ± 5 mrad deviation.

  The lithography beam lb then irradiates the PD device that forms the PD system 102 with the devices necessary to maintain its position. The PD device is held at a specific position in the path of the lithography beam lb that irradiates the opening pattern formed by the plurality of openings 21. As already mentioned, each aperture can be “switched on” or “opened” to allow the beamlet to pass through the respective aperture to reach the target; Transmits the incident beam. Otherwise, the aperture is “switched off” or “closed” when the beam path of each beamlet is affected to be absorbed or otherwise removed from the beam path before reaching the target; The aperture effectively makes the beam opaque or does not pass the beam. The pattern of switched apertures is the only part of the PD device where these apertures transmit the beam lb, and thus the patterned beam pb emerging from the apertures (ie, under the PD system 102 of FIG. 1). Is selected depending on the pattern exposed to the substrate. The configuration and operation of the PD device, particularly with respect to the mekra plate, will be discussed in detail below. In FIG. 1, it is clear that only five beamlets are shown in the patterned beam pb, while the actual number of beamlets is very large; In fact, it is switched off because it is absorbed by the absorption plate 17; the other beamlets switched on pass through the central hole of the plate 17 and are therefore projected onto the target.

  The pattern represented by the patterned beam pb is then projected by the electro-optic projection system 103 onto the substrate 14, where it forms an image of the switched mask opening. The projection system 103 executes optical reduction of 200 times, for example. The substrate 14 is, for example, a silicon wafer covered with a photoresist layer. Wafer 14 is held and placed by the wafer stage (not shown) of target station 104. A detector 15 for secondary radiation can be used to detect the precise positioning of the substrate with respect to the beam.

Projection system 103 preferably consists of two successive electro-optic projector stages with crossovers c1 and c2, respectively. The electric field lens 30 used to implement the projector is shown in FIG. 1 only in symbolic form because the technical realization of an electrostatic imaging system is well known in the prior art; In the field, magnetic and / or electromagnetic lenses are also included as appropriate. In the first projector stage, the plane of the aperture of the PD device is imaged in an intermediate image that is alternately imaged onto the substrate surface by the second projector stage. Both stages use optical reduction imaging at crossovers c1, c2; therefore, the intermediate image is reversed while the final image created on the substrate is vertical (not reversed). The demagnetization factor is about 14 times between both stages, leading to an overall optical reduction of 200 times. This order of optical reduction is particularly appropriate for lithographic configurations because it raises the issue of miniaturization of PD devices. Electro-optic lenses are mainly composed of electrostatic electrodes, but magnetic lenses may also be used.

As a means of introducing a small lateral shift into the image, ie along a direction perpendicular to the optical axis cx, the deflection means 16 are provided in one or both of the projector stages. Such deflection means can be implemented, for example, as a multipole electrode system as discussed in US Pat. No. 6,768,125. In addition, where necessary, a magnetic coil is used to generate a rotation of the pattern in the substrate plane. The lateral deflection is usually very small compared to the lateral width of the patterned beam bp itself, most often the width of the distance between a single beamlet or adjacent beamlets, but below the beam width. (In this context, the lateral distance between beamlets should be recognized as being considerably less than the full width of the beam bp).

  By controlling the pattern formed in the PD system 102, an arbitrary beam pattern can be generated and transferred to the substrate. Optimally, a scan stripe exposure policy is used in which the substrate moves under the incident beam, a beam-scan policy where the position of the beam is constantly changing is not required, and therefore the beam is a single focused beam system It is effectively scanned through the target surface as in the case of (resting or moving slowly at a much lower speed). Details of the exposure policy can be found in the prior art already mentioned, in particular US Pat. No. 6,768,125.

Pattern Definition System, Plate Configuration FIGS. 2 and 3 show the PD system 102 of the apparatus 100. 2 is a top view and FIG. 3 is a combined side and vertical cross-sectional view. FIG. 4 shows details of the cross-sectional view of FIG. 3 that is part of the plate of the PD system 102 along the five beamlet paths. The PD system 102 implements a synthesizer whose components are useful for their respective functions including, for example, a cover plate 201, an aperture plate 202, and a mekura plate 203, so that many plates 22 mounted in a stacked structure Including. In addition, there are also component plates, such as adjustment plates for individual fine adjustment of the beamlet passages (not shown here, see US Pat. No. 6,768,125). Each plate 22 has a structure formed by a film portion formed at the center of the plate representing a PD range pf having a plurality of holes represented by cross-hatching in FIG. Realized as a formed semiconductor (especially silicon) wafer. The lithographic beam traverses the plate through a continuous hole in the PD range pf, as further described below with reference to FIGS.

The plate 22 is an actuator device 241, 242, 243 which is realized as a known type of piezoactuator or nanopositioning element which is attached to the chuck by flexure bonding and fixed with a support structure 24 of the PD system by means of chucks 23 arranged relative to each other Held by. In the vertical direction, the chucks are connected using slidable bearings 25. Preferably, the plate 22 and the chuck 23 are made from the same material, such as silicon, or a material having the same thermal expansion behavior in the operating temperature range. A chuck is also provided for powering the mekra plate 202; for clarity, the electrical lines are not shown.

On the plate 22, a reference mark 26 is provided for the definition of the reference beam. The shape of the reference beam rb is defined, for example, in a hole formed in one of the plates 22, for example the cover plate 201, while the corresponding hole in the other plate is sufficient to allow the radiation for the reference beam to pass through. wide. The reference beam is then imaged with the patterned beam pb; however, in contrast to the patterned beam, the reference beam does not reach the substrate 41, but the alignment system (see US Patent Application No. 2009/0146082 A1). Measured in In addition, the chuck 23 has an alignment opening 236 that serves as a relative position indication for the chuck 23 and alignment marks for the plates 22 that they hold.

  The membrane thickness of each plate 22 is about 30 to 100 μm; if this is appropriate in view of better thermal conductivity, the membrane of the mekra plate is thicker. The plate frame is thicker at approximately 0.750 mm. The distance between the plates is approximately 0.5 to a few mm. In FIG. 4, it should be noted that the size of the vertical axis (z-axis parallel to the optical axis of the device) is not a fixed ratio.

FIG. 4 shows a cross-sectional detail of the membrane portion of the plate 22 of FIG. 3; only the portion corresponding to the five beamlet paths from multiple beamlets in the PD range pf is shown. As already mentioned, the illustrated embodiment allows the second plate 202 to implement an aperture array means within the meaning of the invention, while either the first and third plates 201, 203 are of the invention. A three-plate arrangement consisting of three plates 201, 202, 203 useful as a hole array means is realized.

  The first plate 201 is a cover plate having a pair of holes 210 that define a provisionally shaped beamlet (temporary beamlet). Therefore, the cover plate 201 absorbs the energy of many beams in order to protect the further plate from as much adverse effects as possible of the influencing radiation.

  The second plate is an aperture array means implemented as an aperture plate 202 having a plurality of sets of apertures 221, 222 as further described below. Temporary beamlets in particular reach the openings 221 of the plate 202 and are thus formed in a corresponding number of beamlets b1, b2, b3, b4, b5. For this reason, the hole 210 of the cover plate has a larger width than the openings 221 and 222.

The third plate 203 of the PD system 200 is a deflection array plate, usually referred to as a mekra plate. It has a set of holes 230 corresponding to the passages of the beamlets b1-b5 such that its position is predetermined by the cover plate 201; however, the holes 230 have a larger width than those of the openings 221, 222 ( In other words, the hole 230 is larger) so that the beamlet passes through the former without affecting the mekra plate material. Each aperture 230 comprises electrodes 231 and 232 so that a small but sufficient deflection can be provided to the corresponding beamlet depending on the voltage selectively applied between each pair of electrodes 231 and 232; For example, one electrode 231 is held at ground potential and serves as a counter electrode, while the other electrode 232 is coupled to the circuit layer of the mechla plate 203 for applying a potential to deflect the selected beamlet b1. Useful as an active electrode. Each beamlet can therefore be individually deflected. The mekra plate also includes circuitry for electronic control of the electrodes and electrical supply. Details of the PD device, including the circuit details of the mekra plate, are described in U.S. Pat. No. 6,768,125, U.S. Patent Application No. 2009, as described in assignee / applicant U.S. Patent Application No. Further discussion in / 0200495 A1.

  Each beamlet b1-b5 crosses the next hole in the plate 22 along its nominal path, assuming that the corresponding blanking electrodes 231 and 232 are not energized; Corresponds to the “on” state. A “switch-off” opening is realized by applying a voltage to the electrodes, ie applying a transverse voltage. In this state, as indicated by beamlet b2, the corresponding blanking electrodes 231 and 232 deflect their beamlet b2 away from their nominal path so that the beamlet is preferably a crossover c1, c2 On the blocking opening 17 located around one of the (FIG. 1), it deflects to a different path that eventually (slightly but sufficiently) leads to the absorbing surface.

It should be emphasized that it is the aperture formed in the aperture plate 202 (rather than the first aperture in the cover plate 201) that defines the lateral shape of the beamlet emerging from the PD system 102. Thus, when the term “aperture” is used in connection with the definition of the pattern created in the target, a hole of a defined shape and width (FIG. 6) as defined by the apertures 221 and 222 defining the beamlets in the aperture plate. Means.

The aperture plate and the multiple aperture grid apertures 221, 222 and preferably the corresponding holes 230 in the mekra plate are likewise arranged in a systematic way along a defined grid. Each grid forms a ruled line that runs parallel to the direction corresponding to the relative movement of the image of the aperture above the target, as described, for example, in US Pat. No. 6,768,125. Array. In each line of the offset arrangement, what is offset between successive apertures is preferably a plurality of grid widths underneath the aperture arrangement, while the aperture image is a scan action on the target. The lines pass immediately side by side so that they completely cover the target. The holes shown in FIGS. 5 and 6 show a realization of such a shifted arrangement. In a more general grid arrangement, the aperture is located at an essentially regular two-dimensional grid location, but the grid additionally compensates for such imaging errors due to small deviations in the aperture location and It may have a small deviation from a strict regular grid to account for possible distortions of the imaging system to achieve a strict corrected position of each aperture image above.

  FIG. 5 shows a plan view on a portion of the PD device of FIG. 4 as seen along the direction of the illumination beam. The major parts of the visible surface are occupied by the upper surface of the cover plate 201 which displays a regular array of holes 210 formed in the cover plate. The shape of the corresponding opening 221 through each hole 210 is visible, while the mekra plate is completely hidden by the cover and the opening plate. Line 4-4 represents the line of the cross section shown in FIG.

In accordance with the present invention, the aperture plate includes a plurality of sets of apertures, where each of the sets of apertures can be selected for imaging onto a target.

FIG. 6 shows a detailed plan view of the portion of the aperture plate 202 with the cover plate 201 corresponding to FIG. 5 removed. Line 4-4 represents a partial line for the cross-section shown in FIG. Aperture plate 202 has two interlaced grids of apertures, each referred to as reference numbers 221 and 222, where each grid (with image distortion as discussed in more detail below). Formed with a plurality of apertures of essentially the same shape arranged in an essentially regular array (including small deviations if possible to correct). Either of the two sets of apertures 221 and 222, when viewed alone, form an aperture grid as is known from the prior art, but each has a different aperture shape that allows exposure of different modes of target.

  Referring to FIG. 4a, the aperture plate 202 can be altered by the movement d12 caused by the actuation devices 241, 242, 243 (FIGS. 2 and 3) to actuate the second grid of apertures 222 in the aperture plate 202. . This is in contrast to the position of the opening shown in FIGS. 4 and 5 where the grid of openings 221 is activated. Thus, following positioning on the aperture plate 202 relative to the other plates (see FIGS. 4 and 4a), each grid of apertures 221, 222 is simply sideways to match the corresponding aperture grid of the cover and mekra plate. It can be changed to an accurate position by conversion of. At any time, only one of the grids of apertures cooperates with the holes in the cover and mekra plate to define the shape of the beamlets created in the PD system. In the depiction of FIG. 5, it is emphasized that the opening 222 of the second grid of the aperture plate 202 is hidden by the cover plate 201.

FIG. 7 shows the positioning control of the aperture plate of the present invention. The positioning process of the aperture plate 202 is an actuating supplying Faraday cup 15, a current sensing system 18, a computer or other processor device useful for the positioning controller 19, and an individual actuator represented by the reference symbol dxy. This is achieved by a position control loop as shown which is formed by the control device 20, the aperture plate 202 and the imaging of the aperture in the particle beam device itself. The Faraday cup 15 is moved under the optical column of the particle beam device instead of the separately exposed target 14 during the positioning process. It measures the total amount of beam current _ID that is transferred to the target stage. The beam current _ID depends on the positioning of the apertures associated with the holes in the other plates 22 of the PD system and generally exhibits the maximum amount in accurate alignment. The positioning controller 19 records the beam current as a function of position with respect to the X and Y directions in the -XY plane and the lateral movement of the rotation Rz and optimizes the position of the aperture plate 202 with respect to the positions of the other plates 22. Use the current position current feedback. The actuation control device 20 serves as an interface that converts the control signal from the control device 20 into a signal (eg, voltage) suitable for driving the actuation devices 241, 242, 243 (FIG. 2).

For example, the positioning process is as follows. As a first step, a rough position that matches the grid position of the desired opening shape is set. The coarse position is a pre-programmed or recorded position from a previous positioning process and achieves a positioning accuracy of, for example, ± 50 μm. The aperture plate is then mechanically scanned within the XY plane of the aforementioned positioning accuracy with a predetermined step width, for example 2 to 4 μm (typical beam size) and an angle of 0.5 mrad. The current _ID is recorded during this scan to create a “current map” as a function of position and rotation parameters X, Y, Rz. The maximum current in this current map is then determined using a suitable interpolation technique. If necessary, the step of scanning and evaluating the current map is repeated with a reduced scan step width, in a sub-μm range, for example a partial range determined to include the maximum amount at 0.5 μm. Can do. Finally, if the optimum parameters X, Y, Rz are determined at the maximum position, the aperture plate is moved to this position. The Faraday cup 15 is removed so that the exposure process with the chosen open grid can begin.

In a variant, the positioning process may be performed using a series of reference marks 26 or alignment openings 236 formed in the continuous plate 22 and also on the opposite side (ie above and below the apparatus of FIG. 3). And can be performed by optical alignment in the PD device by controlling the alignment by measuring the amount of light passing through the hole series using a light sensor. Thus, the associated holes 26, 236 used in the aperture plate 202 are replicated with individual examples of holes that are offset from each other in the same manner as the set or aperture.

It should be appreciated that in other implementations of the invention, not all chucks 23 need to be provided with actuation devices for positioning of the respective plates 22. It is clear that the chuck of the plate 201 and / or the actuator for that of the plate 203 is optional if the positioning of the aperture array plate can be adjusted in relation to the other plates. Thus, for example, the plate 201 or plate 203 is held by a chuck that is fixedly mounted within the PD system 102.

  FIG. 8 shows a variation of the PD system configuration 810 having only two plates: an aperture plate 812 and a mekra plate 813. The aperture plate 812 forms a beamlet directly from the beam lb impinging on it. The selection of beamlets is made by controlling the positioning between the aperture 812 and the mekra plate 813. Only the beamlet (shown as a long dashed arrow line) corresponding to the aperture chosen in this way can pass through the mecra plate 813, while the other beamlet (a small dashed arrow ending just above the plate 813). (Shown as a line) is absorbed or stopped on the surface of the mesh plate 813 that is directed towards the incoming beamlet. The mekra plate 813 in this configuration is preferably oriented so that the electrodes and circuitry are located away from the incoming beam (ie, at the bottom of the plate 813 in FIG. 8). In other respects, this configuration has features equivalent to those of FIGS.

The configuration can also be reversed with the mekra plate placed in front of (ie upstream) the aperture plate, as seen along the beam direction. Because of the undesired effects of focused illumination and radiation scattering, the configuration is generally preferred for non-initial plates.

FIG. 9 shows another alternative configuration 820 with a third plate 824 disposed between the aperture plate 812 and the mekura plate 823. Plate 824 passes only the selected beamlet, but stops other beamlets, while Mekura plate 823 is here as a “beam selection plate” that is not in direct contact with radiation and its possible harmful effects. Useful. The beam selection plate 824, which can be easily replaced by itself, thus helps to prolong the life of the mekra plate, which is advantageous because the latter includes elaborate structures of logic circuitry and electrodes. In other respects this arrangement has features equivalent to those of FIGS. 4 to 6 and in particular of FIG.

The present invention allows implementation in any generally suitable number, not just two interlaced grids of openings. FIG. 10 shows an aperture plate 832 having three grids with apertures 931, 932, 933 of different sizes and shapes. The displacements dl2, dl3 between these grids may be along different directions, for example along the right and left X and Y directions of the objective surface of the optical system. The notation used for displacement is a vector that replaces the first set of openings by another set; for example, dl2 indicates a movement that replaces the first set of openings 931 by the second set 932. Here, the position of the first set is indicated (optionally) as a reference. Depending on which displacement is achieved-ie none, one of dl2 or dl3-grids 931, 932, 933 operates as described by the above method.

FIG. 11 shows another advantageous embodiment of the invention, the implementation of different sized pattern ranges. FIG. 11 shows the upper left corner of the pattern range of the aperture plate 842. For example, the first grid of the opening 941 is applied to the first pattern range pf1 extending over the entire range of the film portion, while the second grid of the opening 942 is an extension of the second pattern range pf2. Has a decrease. The sum of the apertures in the second pattern area is similarly reduced because the basic mutual arrangement of the apertures in the grid area is the same (so as to maintain correspondence with the holes in the other plates). The size and shape of the smaller grid openings may be different or similar to those of the larger grid.

  FIG. 12 shows a further advantageous way in which the position of the aperture can be varied by a small amount in the grid to correct the imaging error. These distributions of fine arrangements may also vary in different ways for different grids. For example, one grid opening 951 has little and no deviation from the basic regular arrangement, while the other grid opening 952 introduces a fine arrangement, eg, optical projection system 103. Having such a deviation to achieve pin cushion-like distortion that can correct barrel-like distortion. The range of fine placement deviations (represented exaggerated in FIG. 12) is limited by the size of the corresponding hole in each of the other plates of the PD device. In the typical worst case of 2 nm beam displacement resulting from electro-optic distortion, the center of the aperture must be changed by 200 × 2 = 400 nm, assuming a reduction factor of 200. This distance is usually within the edge of the diameter of the mekra plate hole. Of course, the grids may also have different grid sizes and / or different sizes / opening shapes within each grid; however, if appropriate, they are considered appropriate in each case. As such, the grid size and / or aperture shape is the same.

Claims (13)

A multi-beam pattern definition device (102) used in a particle beam processing or inspection device (100) capable of passing the beam through a plurality of apertures illuminated by a beam of charged particles (lp, bp) In an apparatus adapted to form a corresponding number of beamlets
-An aperture array means (202, 812, 822, 832, 842, 852) realized by the apertures, comprising at least two sets of apertures (221, 222; 931, 932, 933), each of the apertures The set includes a plurality of apertures that are essentially regularly arranged on the aperture array means, the arrangement of the sets being at least partially interwoven, and the different sets of apertures being at least interlaced with the arrangement. Aperture array means that are offset from each other by displacements corresponding to a common displacement vector (dl2, dl3) in the region of interest;
-A hole array means (201, 813, 824) having a plurality of holes (210) configured for the passage of at least a subset of the beamlets formed by the openings, at least in the interlaced arrangement In the region corresponding to the region, the aperture array means comprises a plurality of holes arranged in an essentially regular arrangement, the arrangement corresponding to one arrangement of the set of openings in the region and the other Hole array means lacking holes at locations corresponding to the openings of the set of openings;
Positioning means for positioning at least one of the aperture array means and the hole array means so as to adjust the relative position of the aperture array means with respect to the hole array means, at least of the arrangement weaving Positioning means configured to selectively align a selected set of the set of openings in the aperture array means with the plurality of holes in the hole array means in an intersecting region; Definition device. Further comprising deflection array means (203, 813, 823) having a plurality of blanking apertures (230) positioned such that each of the beamlets traverses one of the blanking apertures along a nominal path. The deflection array means includes a plurality of electrostatic deflection electrodes (232), each associated with a blanking aperture, and when an operating voltage is applied to the respective electrode, the nominal path thereof The apparatus of claim 1, wherein the apparatus is configured to deflect the beamlets traversing the respective blanking aperture in an amount sufficient to deflect the beamlets away from each other. The apparatus of claim 2, comprising at least one hole array means (201, 824) separate from said deflection array means. The apparatus of claim 2 wherein said deflection array means (813) comprises a hole array means. The apparatus of claim 4, wherein the deflection electrode (232) is located on a side of the deflection array means that is oriented away from the incoming beam. 6. A device according to any one of the preceding claims, wherein the sets of openings extend in different but overlapping areas, preferably continuously increasing areas, on the aperture array means. The opening of each set has an equivalent shape and size, while the openings of different sets differ in at least one of their size and shape. Equipment. The aperture array means and the at least one hole array means are like a plate having a membrane portion oriented to be essentially perpendicular to the beam and designed to be disposed in the passage of the beam. The apparatus according to claim 1, which is realized as a simple apparatus. 9. Apparatus according to any one of the preceding claims, wherein the positioning means is configured to adjust the position of only the aperture array means, while the hole array means is fixed within the apparatus. The position of at least one of the apertures of the set deviates from the exact position of a rectangular or diagonal grid due to the fine arrangement displacement, which is an imaging error of the projection system that operates in conjunction with the apparatus. Wherein the position of each of the openings, including its fine displacement, is within a region defined by projection of the corresponding holes of the hole array means onto the opening array means, and Projection is along the direction of the beam under the condition that each set of apertures in the aperture array means is aligned with a plurality of holes in the aperture array means. Equipment. The aperture array means includes a number of subareas having openings, and the positioning means is designed to provide an offset range sufficient to move the aperture array means toward the different subareas. The device according to claim 1. 12. A method for alignment in an apparatus according to any one of the preceding claims, i.e. alignment of one of the set of openings and the holes of the hole array means, with a beam of charged particles. Illuminating the device; measuring the current delivered by the device as a function of changing the relative positioning of the aperture array means and the hole array means with respect to positioning parameters; Determining the value of the positioning parameter at a maximum value of the positioning parameter and adjusting the positioning of the aperture array means relative to the hole array means in accordance with the value of the positioning parameter. A method for multi-beam writing of a particle beam processing or inspection device (100) comprising a multi-beam pattern definition device (102) according to any one of claims 1 to 10, comprising the multi-beam pattern. Writing a first pattern to a surface area on the target using a definition device, wherein the first set of openings of the aperture array means is aligned with the holes of the hole array means; Adjusting the positioning of the aperture array means to align a second set of apertures of the aperture array means with the holes of the aperture array means; and a second pattern on the surface area on the target A step of writing.

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